Rails of this type consist essentially of a horizontal tread and a vertical guide portion. This type of rail has the same purpose as railway rails and is intended to provide both a comfortable and a flat tread which is rated for the loads of the moving vehicles, and lateral guidance for the vehicle traveling thereon.
Concrete rails, in particular, are suitable for track-guided rubber-tired vehicles for reasons of cost and with regard to the reliable frictional resistance or contact between wheel and tread or driving surface. Concrete rails of this type must be able to be produced economically in large numbers and, in this case, must fulfill very high requirements with regard to quality and dimensional accuracy. They are therefore pre-manufactured at the factory as finished concrete parts using very exact shuttering or forms. Whereas the railway rails consisting of steel can be adapted to the shape of the line by bending at the site, bending of concrete rails, especially about the vertical axis, is not possible, since the moment of resistance about this axis is very great. Moreover the friability of the building material does not allow bending in this dimension.
Initial attempts to follow curved lines with straight rails laid polygonally have proved useless in practice, since even with large radii, the periodically recurring breaks in the guide web or portion very quickly lead to a dynamic build-up of steering or guiding movements, which considerably impairs the traveling comfort and safety.
For this reason there has been a change towards producing concrete rails with curved guide portions. This is very expensive, since, for example, with a curve designed with two tracks (two rails per track), segments with four different radii have to be produced. As this example shows, numerous curves with different radii and, therefore, also a plurality of various forms for producing the corresponding concrete rail segments is required for normal rail guidance. The plurality of shutterings or forms required is further increased due to the fact that, at the beginning of the curve and at the end of the curve, transition bends and banking turns also have to be constructed.
It is therefore an object of the invention to construct a form for producing rails of the aforementioned type, so that both straight concrete rails, as well as concrete rails of varying curvature, can be produced by means of the same form.